The invention relates to apparatus for metering two liquids in precise proportions to make a solution having a specific concentration. While the invention has particular application to mixing solutions used for agricultural applications including germicides, disinfectants and other chemicals.
At least in some cases the use of too little concentrate or lower concentration will be ineffective and will not achieve the intended purpose. Also, at least in some cases the use of two much concentrate will produce an undesirable result and/or increase the expense of a given process.
Additional considerations in providing such apparatus are the variation in inlet pressure for at least one of the fluids. More particularly, one of the fluids may be water or other diluent that is provided at tap pressure. This pressure may vary widely, particularly in farm environments. An inlet pressure range of 20 to 120 pounds per square inch is possible.
It is also of great importance to prevent problems with microorganisms in the mixed fluids. More particularly, Pseudomonas is one kind of microorganism that can be a problem with water that is not contained within a pipe. Accordingly, it is essential that the diluent not be exposed to ambient air.
The apparatus must also be capable of meeting various constraints imposed by the United States Food and Drug Administration.
It is an object of the invention to provide metering apparatus that will provide extremely accurate metering of two or more fluids.
It is another object of the invention to provide apparatus that can be used easily without special training.
It is also an object of the invention to provide apparatus which can be mass produced and which will still produce consistent results.
Another object of the invention is to provide apparatus which will function over a very wide pressure range.
Yet another object of the invention is to provide apparatus that will mix fluids with an accuracy of at least 0.1% and preferably an accuracy of 0.01%.